Composite metallic and textile yarn



Jan. 20, 1970 p, BOURGEAS 3,490,224

COMPOSITE METALLIC AND TEXTILE YARN Filed Dec. 10, 1968 Ami United States Patent US. Cl. 57-140 2 Claims ABSTRACT OF THE DISCLOSURE A composite metallic and textile yarn made up of parallel textile filaments and parallel metallic filaments which are formed especially of copper and covered with electrically-insulating material, the assembly of filaments being tightly bound by means of successive laps of textile filaments which are wound in helices of opposite pitch.

This invention relates to composite metallic and textile yarns of the type comprising parallel textile filaments and parallel metallic filaments which are formed especially of copper and covered with electrically-insulating material, said filaments being assembled by means of two successive laps of textile filaments of opposite pitch.

The object of the invention is to form a yarn of this type which is of particularly light weight, which exhibits high tensile strength as well as resistance to abrasion caused by rubbing against the guides through which it is to be passed prior to use and which further exhibits a low coefficient of friction against said guides.

With this objective, the composite metallic and textile yarn in accordance with the invention 'is distinguished by the fact that the parallel textile filaments are formed of a material such as a polynosic material having a value of elongation per unit-length which is close to that of the metallic filaments and that the textile filament of the first lap 3 is formed of a material such as a polyester which has good qualities of strength and elasticity Whilst the textile filament of the second lap 4 is a monofilament formed, for example, of polyester or of superpolyamide such as nylon which is wound in a helix in non-contiguous turns, a space which preferably corresponds approximately to the diameter of said second-lap filament being formed between said turns.

By virtue of the presence of the polynosic filaments, a composite yarn as thus provided has very high tenacity which is such as to retard breakage of the metallic filaments to a considerable extent; by virtue of its high strength and elasticity, the filament of the first lap ensures effective binding of the bundle of parallel metallic and textile filaments; finally, by virtue of its high strength and the fact that it is a monofilament, the second-lap filament serves to bind the assembly in an effective manner and affords particularly high resistance to abrasion. Furthermore, since the turns of said second-lap filament are not contiguous, said filament endows the assembly with an external contact surface which is smaller than that of a smooth yarn, thereby reducting friction.

In an advantageous embodiment, insulation of the metallic filaments is provided by a coating of polytetrafluoroethylene which has the advantage of being of lighter weight than enamel.

A better understanding of the invention will be gained by consideration of the following description and by a study of the accompanying drawings in which the single figure is a large-scale view of a fragment of a composite metallic and textile yarn in accordance with the invention.

The composite yarn which is illustrated in the drawings is constituted by the assembly of two parallel metallic 3,490,224 Patented Jan. 20, 1970 filaments 1 and a plurality (six in the example shown) of parallel textile filaments 2, said filaments 1 and 2 being bound together by means of two successive lap filaments 3, 4 which are wound in helices having turns of opposite pitch.

The two metallic filaments 1 are preferably copper wires in order to provide a low value of electrical resistance over a substantial length and are insulated electrically by means of a suitable coating such as, for example, enamel or alternatively by means of a coating of suitable plastic material which is preferably polytetrafiuoroethylene and which has the advantage of being lighter in weight than enamel.

In a particular embodiment, each of the two copper wires has a diameter of 0.07 mm.

The parallel textile filaments 2 are preferably polynosic filaments which have the advantage of very high strength and of possessing a value of elongation per unit-length which is similar to that of the copper filaments. In the example considered, said textile filaments have a yarn count of 270 deniers.

The first helical textile lap filament 3 is, for example, a 45-denier polyester fiber; by virtue of its high strength and elasticity, said first lap filament ensures efi'ective binding of the bundle of parallel filaments 1 and 2.

Finally, the second lap filament 4 which is finally located at the exterior is wound in a helix of opposite pitch with respect to that of the first lap and in non-contiguous turns. In the example under consideration, said filament which is formed of polyester or of nylon is a monofilament having an external diameter of 0.08 mm., for example, with a helical winding pitch of 0.14 mm. Thus, the turns are not in contact with each other and the outer surface of the finished yarn has a wavy profile, thereby reducing the coefiicient of friction of said yarn against the guides through which it is to be passed.

As will be readily understood, the invention is not limited to the embodiment herein described and illustrated and modifications can accordingly be contemplated, especially in regard to the choice of raw materials as well as the dimensions of the components and the winding pitches of the lapping filaments without thereby departing either from the scope or the spirit of the invention.

What is claimed is:

1. A composite metallic and textile yarn of the type comprising parallel textile filaments and parallel metallic filaments which are formed especially of copper and covered with electrically-insulating material, said filaments being assembled by means of two successive laps of textile filaments of opposite pitch, wherein the parallel textile filaments are formed of a material such as a polynosic material having a value of elongation per unit-length which is close to that of the metallic filaments and wherein the textile filament of the first lap is formed of a material such as a polyester which has good qualities of strength and elasticity whilst the textile filament of the second lap is a monofilament formed, for example, of polyester or of superpolyamide which is wound in a helix in noncontiguous turns, a space which preferably corresponds approximately to the diameter of said second-lap filament being formed between said turns.

2. A composite yarn as claimed in claim 1, wherein the insulation of the metallic filaments consists of a coating of polytetrafluoroethylene.

References Cited UNITED STATES PATENTS 2,508,852 5/1950 Blumfield 57l40 XR 3,206,923 9/1965 Price 57-140 3,288,175 11/1966 Valko 57140 XR JOHN PETRAKES, Primary Examiner 

